GSSI SIR 4000, Руководство пользователя

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Geophysical Survey Systems, Inc. SIR® 4000
Manual
MN72-433 Rev F 17
Assuming your Antenna Transmit Rate is 200 KHz, the scans/second should be at least 240 whenever you
are collecting with a survey wheel and are collecting a maximum of 512 Samples/Scan.
If you set Scans/Second higher than the selected transmit rate and the number of samples/scan, the
SIR 4000 will lower it to the maximum possible. However, it is recommended that the scans/second be
set lower than the maximum. This will allow the system to auto stack points thereby improving the signal
to noise ratio.
Samples/Scan
Each scan curve is made up of individual data points, called
Samples. More samples generate a smoother the scan curve
and improve vertical resolution. This also affects scan speed;
more points collected means lower maximum scans/second.
•
You can choose from a preset list of 256, 512, 1024,
2048, 4096, 8192, or 16384 samples/scan. FIR filters
should only be used with 256-2048 samples/scan.
•
As sample number increases, max scan rate drops
and file size increases.
•
GSSI recommends sampling at 512 or 1024
samples/scan for most applications. More samples
will be required for deep geologic or polar ice
thickness applications. Below is the equation to use
when choosing a sample rate.
Scans/Unit
Scans/Unit adjusts the number of scans per unit of horizontal distance. This parameter is the scan spacing
when you are collecting with the survey wheel. The unit of measure is based on the Units selected from
the Introduction Screen and the Horizontal Units selected from the Output Menu.
•
Smaller scan spacing: produces higher resolution data, creates larger file sizes, and may require
slower data collection. For example, if Scans/Unit is set to 12 and the system is set to English feet
(rather than Metric units) you will collect 12 scans per foot, or 1 per inch.
•
Scan spacing can be customized for certain applications. For example, 5-10 scans/inch (60-120
scans/foot) is the optimal range for shallow structural features in concrete. With lower frequency
antennas, like a 400 MHz, a coarser scan density of 12-24 scans/foot is typical.
Units/Mark
You can also set how many units (i.e., feet or meters) will be collected between system marks. These
marks will appear at the top of the data display along the horizontal scale.
Static Stacking
This option is only available in Point Mode. It uses the number of scans entered and averages them to
output a single composite scan at each location. This function minimizes high-frequency or random noise.
Antenna
Model
Frequency
(MHz)
Pulse
Duration
(ns)
42000S 2 GHz Horn 0.5
41000SA 1 GHz Horn 1
52600S 2.6 GHz 0.4
62000 2 GHz Palm 0.5
51600S 1.6 GHz 0.7
5101 1 GHz 1
3101A 900 MHz 1.1
50400S 400 MHz 2.5
50270S 270 MHz 3.7
5106 200 MHz 5
3207 100 MHz 10
Samples/Scan > ((10*Time Range)/Pulse Duration)